A variety of devices exist which make use of cables or tubes for delivering electrical signals, fluids, etc. from a medical device to a region of the body, or simply for holding device(s) in place. For example, electrical lead cables, i.e., leads or lead extensions that detachably connect to an electrical device or to other lead cables may deliver electrical stimulation to a nerve, muscle, or other tissue. For instance, numerous medical devices, such as neural stimulation devices, cardioverters, cardiac pacemakers, and defibrillators, commonly establish a connection between an implanted lead or lead extension (both will be referred to herein as lead cables or simply leads) and an implanted electronic package. In a typical pacemaker, the proximal end of a lead may be removably connected to a lead extension, which in turn is removably connected to an implantable pulse generator. The distal end of the lead, containing one or more electrodes, is typically inserted in or on the heart.
The most effective position of the electrodes or other devices at and/or along the distal end of the lead is commonly determined during surgery. Once the lead is implanted in this preferred position, it generally must be secured to surrounding tissue to prevent it from becoming dislodged. Accordingly, a lead anchor (also often referred to as a suture sleeve) that surrounds or is a part of a lead cable may be provided.
Various techniques and mechanisms have been proposed for securing implanted or partially implanted leads in a patient. In the early 1970's, “butterfly” type anchoring sleeves were provided with the lead, the anchoring sleeve being adapted to be sutured to a vein or underlying tissue. The anchoring sleeve was attached to the lead body during implantation, and protected the lead insulation from the stress of having a suture tied around it. When polyurethane leads were introduced in the late 1970's, the leads were frequently provided with a pre-fitted sleeve, typically formed of silicone rubber, to facilitate securing the lead with sutures. When installing the lead and sleeve, the physician would secure the lead by sliding the sleeve to a position near where the lead enters the vein, and suturing the sleeve to the vein or to underlying tissue.
Several examples of prior art suture sleeves are known in the prior art or are the subject of patent disclosures, including the following: U.S. Pat. No. 4,276,882 to Dickhudt et al. entitled “Lead Anchoring Device”; U.S. Pat. No. 4,516,584 to Garcia entitled “Suture Collar”; U.S. Pat. No. 4,553,961 to Pohndorf et al. entitled “Suture Sleeve with Structure for Enhancing Pacing Lead Gripping”; U.S. Pat. No. 4,672,979 to Pohndorf entitled “Suture Sleeve Assembly”; U.S. Pat. No. 4,683,895 to Pohndorf entitled “Suture Sleeve Anchoring Device”; U.S. Pat. No. 5,107,856 to Kristiansen et al. entitled “Multiple Lead Suture Sleeve”; U.S. Pat. No. 5,129,405 to Milijasevic et al. entitled “Vein Suture Collar”; U.S. Pat. No. 5,273,053 to Pohndorf entitled “Suture Sleeve With Lead Locking Device”; U.S. Pat. No. 5,476,493 to Muff entitled “Implantable Lead Having Self-Locking Suture Sleeve”; U.S. Pat. No. 5,603,730 entitled “Suture Sleeve for Implantable Lead”; U.S. Pat. No. 5,628,780 to Helland et al. entitled “Protective, Visible Suture Sleeve for Anchoring Tran venous Lead Bodies”; U.S. Pat. No. 5,683,446 to Gates entitled “Medical Electrical Lead Having an Anchoring Sleeve Retaining Device”; U.S. Pat. No. 5,746,722 to Pohndorf et al. entitled “Suture Sleeve With Circumferential Lead Locking Device”; U.S. Pat. No. 5,843,146 to Cross, Jr. entitled “Adjustable Medical Lead Anchor”; U.S. Pat. No. 5,957,968 to Belden et al. entitled “Suture Sleeve With Lead Locking Device”; and U.S. Pat. No. 6,473,654 to Chinn entitled “Lead Anchor”.
Other types of securing devices are disclosed, for example, in the following references: U.S. Pat. No. 3,176,690 to H'Doubler entitled “Catheter Having Integral, Polymeric Flanges”; U.S. Pat. No. 3,724,467 to Avery et al. entitled “Electrode Implant for the Neuro-Stimulation of the Spinal Cord”; U.S. Pat. No. 3,821,957 to Riley et al. entitled “Retention Slide for Catheters and Other Tubular Materials”; U.S. Pat. No. 3,880,169 to Starr et al. entitled “Controlled Entry Pacemaker Electrode for Myocardial Implantation”; U.S. Pat. No. 4,266,552 to Dutcher et al. entitled “Lead Anchoring Bobbin”; U.S. Pat. No. 4,276,882 to Dickhudt et al. entitled “Lead Anchoring Device”; U.S. Pat. No. 4,287,891 to Peters entitled “Securing Device”; U.S. Pat. No. 5,484,445 to Knuth entitled “Sacral Lead Anchoring System”; U.S. Pat. No. 5,690,616 to Mogg entitled “Catheter Clamp”; U.S. Pat. No. 6,361,523 to Bierman entitled “Anchoring System for a Medical Article”; U.S. Pat. No. 6,929,625 to Bierman entitled “Medical Line Anchoring System”; and U.S. Pat. No. 6,972,003 to Bierman et al. entitled “Medical Anchoring System”.
Known anchoring sleeves have several disadvantages. Early anchoring sleeves displayed a high rate of migration. While anchoring sleeves have improved over time, firm plastic anchoring sleeves such as those including relatively firm components that rotate relative to one another along the axis of the lead often acted as a fulcrum and allowed some motion such that patients could feel the placed device. Additionally, such devices likewise migrated over time.
While softer or silicone rubber suture sleeves offered some advantages over prior art, known silicone rubber suture sleeves likewise have several disadvantages. Sleeves which must be placed on the lead during manufacture can only be removed by cutting them off, as with a scalpel, when physicians do not wish to use them. This is considered undesirable, since there is a risk that the insulation of the lead would be damaged while the sleeve was being cut off. Moreover, when a silicone rubber suture sleeve becomes wet or infiltrated by moisture, the friction between the lumen of the sleeve and the lead may be reduced so much that the lead is allowed to slide, and is no longer anchored in place.
The lead anchor may require the physician to use, for instance, suture material to secure the anchor to the lead cable. Generally, lead anchors are configured to allow a physician to wrap suture(s) around and/or through the lead anchor multiple times, while securing the sutures to the adjacent tissue.
While securing the lead anchor to the lead cable and while securing the anchor (and thus the lead) to the adjacent tissue, a common problem is under-tightening of the sutures, which may result in inadequately securing the lead. Anchors typically stipulate the use of three separate sutures in order to keep the anchor tight against the lead. Even with three sutures, anchors often do not sufficiently secure the lead. Conversely, over-tightening of the sutures may result in stresses that can damage the wires within the lead cable and/or break the insulation, which may ultimately cause the lead to fail. Thus, the compression force created by using sutures depends on technique, skill level and accessibility of the suture sleeve in the wound site. Preferably, a lead anchor should provide a consistent clamping force that is not dependent of suturing technique, skill level or position in the wound site, and would preferably reduce the opportunities for any lead damage.
Securing the lead in place should be simple, to reduce surgical time, and evident, to limit chances for error. The lead anchor is preferably slidable along the lead so it may be positioned appropriately for different implant locations and for a variety of patient body types. Multiple lead anchors per lead cable may be useful in some situations.
The lead anchor is preferably compact and light-weight, and constructed of biocompatible materials. Once properly secured, the connection between the anchor and lead cable should be strong enough to resist pulling and any other forces that could unintentionally disconnect the lead cable from the surrounding tissue.
There exists a need in the art for a compact, easy to operate, fast, and reliable way to secure a tube or cable, such as a lead cable, to surrounding tissue that limits the likelihood of damage to the tube or cable.